Ulcerative Colitis is an inflammatory disorder of the large bowel (colon and rectum) of unknown cause. It is usually worse in the rectum and may extend for varying distances along the colon proximally (and may involve the entire colon). There are other types of inflammatory disorders of the large bowel which are sometimes confined to the rectum which may be a very mild form of ulcerative colitis or a slightly different syndrome with very similar pathology. Crohn's Disease is yet another type of inflammatory bowel disease of unknown etiology which also affects the large bowel occasionally. There is no known cause for these conditions and the approach to treatment has been the use of non-specific anti-inflammatory drugs. The most effective treatment is the use of steroid drugs which are potent anti-inflammatory agents, but these also have a wide variety of side effects which include suppression of the hypothalamic pituitary adrenal (HPA) axis. These steroid drugs (e.g. prednisone) are most commonly given orally and occasionally parenterally. They are absorbed and produce their therapeutic effects on the colon as part of their broad anti-inflammatory action but because they enter the system circulation their major side effects are not avoided.
Many steroid drugs have very potent topical activity which has been successfully utilized in the treatment of asthma and certain skin disorders. However, since absorption occurs even through the skin, they also produce the same side effects when applied to the skin, as steroids taken systemically.
It has been a practice hitherto to treat patients with inflammatory bowel disorders such as distal ulcerative colitis, by administering a steroid drug as an enema. Whilst this applies the drug primarily to the location where its topical treatment effects are required, it is well recognized that the drug still enters the systemic circulation and results in side efffects. This occurs with the smallest doses of steroid enemas likely to be effective (e.g. 5 mg. betamethasone or 100 mg. hydrocortisone enema every night).